|This exercise lets you practice blocking
out visual distractions. Your mission, should you choose to accept
it, is to keep your attention on the centre of the target below, ignoring
the mild distractions to the sides, until the game is over. The first
distraction takes about 5 seconds to appear, and the sequence is about
two minutes long. The end is signalled with a 'end of game' message.
Press Go to start.